OPTICAL MEDIA DETECTION SYSTEM

摘要

An optical media detection system (10) is described. The system (10) comprises a light source (16), a transmitted light detector (18), and a reflected light detector (20). The source (16) and the detectors (18, 20) are mutually arranged and oriented such that the reflected light detector (20) detects light reflected from a portion of a media item (14) irradiated with light from the source (16), and the transmitted light detector (18) detects light transmitted through the portion of the media item (14) irradiated with light from the source (16). When a substantial amount of light is transmitted and reflected from a portion of the media item (14) then this indicates that the portion of the media item (14) irradiated is an optically transparent window, thereby enabling the system (10) to distinguish between a transparent window and a void.